Certain installations are designed to allow the laying of elongated bodies, in particular cables or pipelines, along water areas.
Such installations are mainly met on floating structures, such as ships or off-shore platforms, for a laying along sea floors.
Such laying installations generally comprise a tower on which is added at least one laying device of the tensioner type.
The so-called “tensioners” laying devices ensure a handling by clamping of a segment of the elongated body, and the piloted moving of the latter, to allow the controlled laying thereof on the chosen receiving surface.
More precisely, a first role of the tensioner is to constantly clamp the cable or the pipeline in an efficient manner, taking into account the fact that the weight of the part of the elongated body that is transferred out of the floating structure increases significantly as the laying operation goes along.
The second role of the tensioner is to manoeuvre the elongated body to ensure the longitudinal displacement thereof, in a controlled manner. The speed of laying depends in particular on the time required for assembling cable or pipeline portions.
For that purpose, the tensioners conventionally comprise an annular frame that defines a passage for the circulation of the elongated body and that carries guiding boxes arranged about a passage axis of said passage of circulation for the clamping of a segment of the elongated body.
However, the elongated body is liable to carry pieces of equipment, such as connectors or bottom pieces of equipment, which have a cross section whose diameter is higher than the mean cross section of the elongated body, but also than the diameter of the passage of circulation.
To take this constraint into account, certain tensioners are “openable”, as described for example in the patent FR-2 970 056.
The corresponding tensioner comprises a frame composed of two half-frames that are assembled, through pivot means, to a sleeve for the fixation of the tensioner to the tower.
These pivot means are arranged so as to allow a rotational operation of the half-frames between closed/open configurations, each one about a proper rotation axis.
But such an “openable” tensioner is liable to undergo significant constraints and efforts on its half-frames in the open position, liable to complicate the closing thereof.